Heat and ozone resistant NBR/epichlorohydrin blends

Abstract

Cured blends of acrylonitrile/butadiene (NBR)/epichlorohydrin rubbers are provided that are free of poisonous lead compounds with ozone resistance of 10 hours or more and good heat resistance and fuel and oil resistance. These acrylonitrile/butadiene rubbers contain 28 to 33% by weight of acrylonitrile. The epichlorohydrin rubbers are useful in this invention which contains at least 4 to 12% of allyl glycidyl ether and may contain 0 to 35% of ethylene oxide, preferably 2 to 6% and up to 15%. The acrylonitrile/butadiene rubber is preferably of so-called bound antioxidant type which contains about 1 to about 10% by weight of polymerized attached antioxidant containing monomer.

What is claimed is: 
     
       1. A blend of (1) acrylonitrile-butadiene bound antioxidant terpolymer rubber comprised of a polymer of acrylonitrile-butadiene-N(4-anilinophenyl)methacrylamide and (2) a epichlorohydrin rubber, said bound antioxidant terpolymer rubber containing from 28% to 33% by weight of acrylonitrile and is present in blend in about 75% to 25% and said epichlorohydrin being selected from the class consisting of a copolymer of epichlorohydrin and allyl glycidal ether and a terpolymer of epichlorohydrin, allyl glycidal ether and ethylene oxide, said allyl glycidal ether being present in the epichlorohydrin in an amount of about 4 to about 12% by weight and is present in blend in about 25 to about 75% and the ethylene oxide being present in terpolymer in 15 to 35% by weight. 
     
     
       2. The blend of claim 1 cured with a peroxide curative. 
     
     
       3. The blend of claim 1 wherein the blend contains about 50 to about 10% of epichlorohydrin polymer and about 50 to about 10% acrylonitrile/butadiene polymer. 
     
     
       4. The blend of claim 2 further comprising at least 50% by weight of a mineral filler. 
     
     
       5. The blend of claim 2 further comprising a filler other than carbon black. 
     
     
       6. The blend of claim 3 wherein the blend further comprises silica. 
     
     
       7. A blend of bound antioxidant acrylonitrile-butadiene rubber comprising polymer of acrylonitrile-butadiene-N(4-anilinophenyl)methacrylamide and a epichlorohydrin rubber, said acrylonitrile-butadiene rubber containing from 28% to 33% by weight of acrylonitrile and is present in blend in about 90% to 10% and said epichlorohydrin being selected from the class consisting of a copolymer of epichlorohydrin and allyl glycidal ether and a terpolymer of epichlorohydrin, allyl glycidal ether and ethylene oxide, said allyl glycidal ether being present in the epichlorohydrin in an amount of about 4 to about 12% by weight and is present in blend in about 10 to about 90% and the ethylene oxide being present in terpolymer in 15 to 35%. 
     
     
       8. The blend of claim 7 cured with a peroxide curative. 
     
     
       9. The blend of claim 7 wherein the blend contains about 50 to about 10% epichlorohydrin polymer and about 50 to about 10% acrylonitrile/butadiene polymer. 
     
     
       10. The blend of claim 8 further comprising at least 50% by weight of a mineral filler. 
     
     
       11. The blend of claim 8 further comprising a filler other than carbon black. 
     
     
       12. The blend of claim 9 wherein the blend further comprises silica. 
     
     
       13. The blend of claim 7 wherein the epichlorohydrin rubber contains 29 or more percent chlorine and at least 11% of allyl glycidal ether.